import cv2
import numpy as np

def nothing(x):
    pass


# 创建一副黑色图像

img = np.zeros((300, 512, 3),np.uint8)
cv2.namedWindow("image")

cv2.createTrackbar("R", "image", 0, 255, nothing)
cv2.createTrackbar("G", "image", 0, 255, nothing)
cv2.createTrackbar("B", "image", 0, 255, nothing)

switch = "0:OFF\n1:ON"
cv2.createTrackbar(switch, "image", 0, 1, nothing)

while True:
    cv2.imshow("image", img)
    k = cv2.waitKey(1) & 0xff
    if k == ord(" "):
        break
    
    r = cv2.getTrackbarPos("R", "image")
    g = cv2.getTrackbarPos("G", "image")
    b = cv2.getTrackbarPos("B", "image")
    s = cv2.getTrackbarPos(switch, "image")

    if s==0:
        img[:] = 0
    else:
        img[:] = [b, g, r]
        img[:,0:5,:] = 255
    pass

cv2.destroyAllWindows()